Insecticide Evaluation, 1989

Abstract

Abstract Insecticides were applied to 6 single-tree plots (3 'Rome Beauty', 3 'Golden Delicious') of 35-yr-old trees in a randomized block design. Applications were made with a Swanson DA500A airblast sprayer which traveled at 2.4 mph and delivered a spray volume of 100 gal/acre. Dates of application were 4 Apr (delayed dormant [DD]), 19 Apr (prepink [PP]), 9 May (petal fall [PF]), 26 May (first cover [1C]), 10 Jun (second cover [2C]), 23 Jun (third cover [3C]), 8 Jul (fourth cover [4C]), 25 Jul (fifth cover [5C]), 8 Aug (sixth cover [6C]), 23 Aug (seventh cover [7C]) and 6 Sep (eighth cover [8C]). Other materials applied separately to all treatments were Bayleton, Benlate, Dikar, Dodine, Folpet, Manzate 200, Rubigan, Solubor, and Streptomycin. Control of RAA was evaluated by counting colonies on each tree. The effect of treatments on WALH was determined by counting nymphs on 25 leaves selected from the periphery of each tree. Treatment effect on ERM was determined by sampling 33 leaves from the periphery of each 'Rome Beauty' tree, removing mites with a mite-brushing machine, and counting active stages with a binocular microscope. Control of STLM was evaluated by counting mines observed in 5 min while walking around the periphery of each tree. The effect of treatments on fruit-feeding insects was determined by scoring for injury 600 apples/treatment (100/replication) plus all fallen apples sampled on 25 Sep. Fruit picked from 'Golden Delicious' trees were rated for finish on a scale of 0-5, 5 being worst.